Field of the Invention
The present invention relates to a wire forming apparatus which works a wire into a desired shape.
Description of the Related Art
A conventional wire forming apparatus sometimes needs to perform a process of rotating a fed wire in addition to a process of bending, curving, or winding the wire in order to work the wire into a final product shape. The conventional wire forming apparatus performs a process of rotating a wire by using feed rollers which feed the wire to a forming table. That is, this apparatus rotates a wire by making a pair of feed rollers pivot around the wire axis through a desired angle while compressing the wire between the pair of feed rollers. An advantage in rotating a wire is that it is possible to easily form the wire in an arbitrary direction. In other words, when not rotating a wire, it is necessary to change the mount positions of tools.
The long wire supplied from a material maker is held while being wound around a wire supply mechanism. For this reason, the wire has a curving tendency with a large curvature so as to curve in the winding direction. A curving tendency correction mechanism corrects this curving tendency to some extent when feeding out the wire, but cannot completely eliminate the tendency. For this reason, if a thin wire having a wire diameter of about 0.3 mm or less, in particular, is rotated with this tendency remaining, the direction of the curving tendency changes vertically or horizontally every time it is rotated. This affects the working of the wire, leading to, for example, variations in final product shape. In the process of rotating the wire, although the wire is compressed by the pair of feed rollers, rotating the wire repeatedly for a long period of time will cause a slight slip between the feed rollers and the wire. The accumulation of such slips will make product shapes unstable. In addition, the above process of rotating the wire twists the wire between a rotating wire supply mechanism and the feed rollers. This influences the stability of product shapes. Although securing a sufficient distance from the wire supply mechanism to the feed rollers can reduce the influence of twisting, it is not possible to completely eliminate the influence. The smaller the line diameter of a wire, the greater the influence.
For example, Japanese Patent No. 5148759 has proposed a wire forming apparatus which can rotate a tool around the axis of a wire without adding any process of rotating the wire. Japanese Patent No. 5148759 discloses a structure in which a plurality of tool slides 16 are radially arranged on a swivel table 10, and driving mechanisms corresponding to the number of the tool slides 16 are radially arranged on a forming table 2 around the swivel table 10.
According to Japanese Patent No. 5148759, the plurality of tool slides 16 are radially arranged on the swivel table 10, and the driving mechanisms corresponding to the number of the tool slides 16 are radially arranged on the forming table 2 around the swivel table 10.
In order to always make a tool drivable regardless of the rotational position of the swivel table 10, driving mechanisms corresponding to the number of tool slides 16 need to be arranged on the forming table 2. In addition, according to Japanese Patent No. 5148759, when rotating the swivel table 10 to which the tool slides 16 are attached, it is necessary to retract the driving mechanisms on the forming table 2 backward.